Henry looks up at my face in the middle of his push-up to see if I’m watching him.

I am. I can’t not watch him. It’s pretty much impossible.

It’s around 7 in the evening and we’re both down on the rug exercising. I’ve been doing this pretty steady for the past year; no matter how tired I am at the end of the day, I get Charlie, 1, to bed in his crib, set up Violet, 6, with my laptop and some PBS Kid’s games upstairs, and then I do my little workout routine downstairs in the living room.

Henry, 4, does not miss a session. Ever. Oh, sometimes he drifts — walks out on doing squats to head into the playroom only to appear a few minutes later dressed in a full Hulk costume, but that only makes it better. I mean, who doesn’t want to work out with the Hulk?

Tonight though, he’s doing his push-ups right alongside me, syncing them up with mine, even dragging his high-pitched voice down a couple levels to a near growl just so he can sound more like me as we count off our reps.

And right this second, he is looking hard at me. And so I keep looking at him. He wants me to watch him do some push-ups on his own. He doesn’t need to tell me he wants me to watch, I can just feel it.

And so I watch. His push-ups are more like he’s doing The Worm, which is fine with me. My kid wants my approval and I’m about to give it to him, a massive dose of high-fives and “Yeah, man!”

As far as I can tell, life nails a dad straight in the heart when his son reaches this age, moving me in ways I have never quite known before. It’s game-changing stuff, the sort of realization that only comes once in a lifetime: this kid I am so in love with wants to be exactly like his father.

Like me, he wants to be like me.

That’s the most magnificent thing that has ever happened to me. And to be honest, I don’t think I was prepared for it. Not with my son, anyway. My older daughter Violet and I have always been extremely close. Since the day she was born, I’ve been way up in every possible angle of her life, and our love has always been everything I could ever dream of.

But with Henry, things are a little different. Violet never followed me around from room to room all that much. Not like Henry does.

I walk over to the kitchen table and grab an apple — Henry moves in my footsteps and grabs an apple too. I cross my legs as we watch a movie together on the couch, and before long I’ll notice Henry crossing his legs the same way. A lot of times, I don’t think he’s even conscious he’s doing it. It seems as if he’s wired this way, to love me so much that his little body mimics mine.

It is, I daresay, the most magical thing that has ever happened to me. You see, like Henry, I was a child of divorce. But the one glaring difference is that my dad left when I was very young, vanishing in the night, and so I spent a good portion of my youth without a daddy to copy or mimic. I never let it get to me, probably because I never knew any better.

Yet with Henry, I see this whole chance to turn it all around. Like I’m able to reclaim what I lost in a weird way. By being this guy that my little boy looks up to, it’s as if I’m getting paid back a trillion times over for never having a dad of my own.

And so when we’re both down on the rug doing push-ups in the evening and this kid of mine keeps glancing over at me to see if I’m clocking him doing his exercises, nothing is lost on me. My entire existence — my entire life — feels so worthwhile and monumental in those simple, easy moments.

To have that sort of responsibility as a father is nothing short of a miracle for a dude like me. And I just want to get it right. I really do. Because I never imagined myself in this position. I never dreamed I’d be so in love with a young fellow who can’t even begin to downplay how in love he is with me.

I never dreamed I’d get the chance to be the daddy I never had.

But my own son is changing all that, a thousand times an hour, a million times a day.